As shown in FIG. 1, a conventional high chair 9′ (or a stroller) mainly comprises a seat portion 1′, a backrest 2′, an arm 12′, a frame 4′, a plurality of wheels 8′ and a tray 3′, all of which are pivotally connected together. However, when the conventional high chair 9′ is collapsed, only the frame 4′ can be collapsed into two parallel bars or moreover the backrest 2′ is adjusted to parallel with the frame 4′, but the angle between the seat portion 1′ and the frame 4′ can by no means be adjusted. Therefore, the front-rear seat portion 1′, almost perpendicular to the frame 4′, has a large longitudinal size and thus not only lots of packing material is consumed but also too much transportation space is occupied. It consequently wastes the packing material, increases the transportation cost and is inconvenient for users to carry the high chair 9′ outdoors.
On the other hand, the conventional high chair 9′ only has a button (not shown) for collapsing the high chair 9′. Hence, if the button is mistakenly pressed or broken down, the infant in the high chair 9′ may drop down or be jammed.